1. Field of the Invention
This invention relates to the water-tight connection of pipes, and, more particularly, to the connection of pipes for low-pressure water systems.
2. Description of the Prior Art
Low pressure water systems, such as used in evaporative coolers, include various types of connections in the water system. For example, evaporative coolers include a reservoir usually connected to a standard water supply. Within the reservoir there is a standpipe to limit the height of the water within the reservoir. The standpipe is connected to the reservoir in a fluid-tight connection. There are many other types of systems which must be connected to a water supply through some type of water-tight connection. There are many other types of systems which must be connected to a water supply through some type of water-tight connection. Most apparatus requiring fluid-tight couplings include threaded fittings, or connections.
Threaded connections for water-tight conduits are typically made of brass, with machined threads externally and internally. A gasket is needed to insure that the threaded connection remains water-tight. Relatively expensive tooling, etc., is required.
Threaded connections may also be made of various types of plastic or polymer materials. External threads may be cut into molds and accordingly machining is not required. However, internal threads are difficult and relatively expensive to make.
A typical use application for a fluid-tight connection is found in evaporative cooler standpipes. The use of galvanized pipe is, or has, given away to the use of plastic pipe for such applications.
Evaporative coolers include a water reservoir and a pump in the reservoir that supplies water to soak cooler pads. The pumped water flows downwardly through the pads by gravity and the excess water returns to the reservoir. To maintain a predetermined amount of water in the reservoir, a source of water is connected to the reservoir. The height of the water in the reservoir is typically controlled by a float valve connected to the input source. However, the float valve may sometimes malfunction, and in such case, the input water keeps flowing into the reservoir, and an overflow pipe is used to drain away the excess water. When the water level reaches the top of the standpipe or overflow pipe, the excess flows into the overflow pipe, and into a hose generally connected to the pipe, which drains away the excess water.
The simplest form of the prior art comprises a vertically extending pipe secured to the bottom pan of an evaporative cooler. The pipe is of a predetermined length, and is simply threaded into some type of bushing or pipe fitting which is in turn connected to a hose. The hose allows the water flowing into the standpipe or overflow pipe to drain away from the evaporative cooler. The vertical height of the pipe is preferably fixed, but it is difficult to consistently provide for the same overflow level due to the threaded engagement of the pipe. Due primarily to the electrical components in the cooler, a predetermined and consistent maximum height or level of the water is highly desirable.
The problem of sealing the standpipes and of adjusting or determining the vertical height of the standpipes are problems which are very real. The threaded engagement of the mating pipes comprises the seal in the prior art. That is, the seal is dependent upon the threads of the pipe fittings.
Another problem is the economics of metal pipe versus plastic pipe. The cost of metal (galvanized steel) pipe, which resists the attack of the corrosive salts in the water, is greater than the cost of plastic pipe, which also is corrosion resistant. However, fabrication of internal threads in plastic pipe is an expensive process.
While plastic pipe has a general cost advantage over galvanized steel pipe, the cost involved in fabricating internal threads within the plastic pipe substantially decreases the attractiveness of plastic pipe as an alternative to galvanized steel pipe.
Another problem of the prior art is the inability to adapt overflow pipes to flat or shallow sloped roofs. If a hose is coupled directly to a pipe, there is a likelihood of kinking which prevents water from running through the hose, and thus blocks the overflow pipe.
The apparatus of the present invention is adaptable to rooofs of varying slopes, and solves the prior art problems of seals and threads, all with plastic material. Moreover, a substantially uniform height of the overflow pipe is consistently obtained.
Of primary importance in evaporative cooler standpipes is a water tight connection of the standpipe and any train line connected to it and a water tight connection with the evaporative cooler housing floor. A threaded connection is used to connect the several components together. In the apparatus of the present invention, both a tapered connection and an internal thread having less than a complete, helical thread length of less than three hundred sixty degrees are used. The parts or elements are made of a plastic or polymer material, amenable to molding techniques.
Threaded connections of various types, involving either a tapered connection or a thread of very few turns, or both, are shown in U.S. Pat. Nos. 2,454,465; 3,281,869; 3,404,540; 3,540,757; 3,749,424; 3,876,234; and 4,212,335.